A high-confidence interaction map identifies SIRT1 as a mediator of acetylation of USP22 and the SAGA coactivator complex

Mol Cell Biol. 2013 Apr;33(8):1487-502. doi: 10.1128/MCB.00971-12. Epub 2013 Feb 4.

Abstract

Although many functions and targets have been attributed to the histone and protein deacetylase SIRT1, a comprehensive analysis of SIRT1 binding proteins yielding a high-confidence interaction map has not been established. Using a comparative statistical analysis of binding partners, we have assembled a high-confidence SIRT1 interactome. Employing this method, we identified the deubiquitinating enzyme ubiquitin-specific protease 22 (USP22), a component of the deubiquitinating module (DUBm) of the SAGA transcriptional coactivating complex, as a SIRT1-interacting partner. We found that this interaction is highly specific, requires the ZnF-UBP domain of USP22, and is disrupted by the inactivating H363Y mutation within SIRT1. Moreover, we show that USP22 is acetylated on multiple lysine residues and that alteration of a single lysine (K129) within the ZnF-UBP domain is sufficient to alter interaction of the DUBm with the core SAGA complex. Furthermore, USP22-mediated recruitment of SIRT1 activity promotes the deacetylation of individual SAGA complex components. Our results indicate an important role of SIRT1-mediated deacetylation in regulating the formation of DUBm subcomplexes within the larger SAGA complex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Cell Line
  • HEK293 Cells
  • Humans
  • Mutation
  • Protein Binding
  • Protein Interaction Maps*
  • Protein Processing, Post-Translational
  • RNA Interference
  • RNA, Small Interfering
  • Sirtuin 1 / genetics
  • Sirtuin 1 / metabolism*
  • Thiolester Hydrolases / genetics
  • Thiolester Hydrolases / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Ubiquitin Thiolesterase
  • Ubiquitination

Substances

  • RNA, Small Interfering
  • Trans-Activators
  • Thiolester Hydrolases
  • Ubiquitin Thiolesterase
  • Usp22 protein, human
  • SIRT1 protein, human
  • Sirtuin 1